The invention concerns a trocar in the form of a flexible access tube for insertion into body cavities, preferably with the use of an invertible hose system for diagnosis and surgical interventions, particularly in the colon area.
The invention especially concerns a flexible access tube whereby diagnoses can be performed, for example by inserting a coloscope, as well as operations in accordance with the minimally invasive surgery technique, by inserting corresponding surgical instruments into the access tube through the anus. Among other things, this new type of flexible access tube thereby takes over the function of trocars known until now, and for reasons of simplification will be called a xe2x80x9cflexible trocarxe2x80x9d in the following.
When striving towards ever better and more specialized surgical techniques, whereby ever smaller operating areas suffice and are therefore less demanding on the patient""s organism, the technically meaningful application of the so-called minimally invasive surgery technique is constantly expanded with the development of new instruments and auxiliary means. Diagnoses as well as complete operations are already being performed on human organs by inserting so-called trocars as auxiliary surgical means through the abdominal wall or the thorax, through which surgical instruments as well as optics can be moved to the organ to be diagnosed or operated.
Such auxiliary means and instruments however cannot be used in all cases.
For example, to surgically remove large tumors such as carcinomas etc. from the colon, except for the end area of the intestine, according to conventional usage required a major operation until now, i.e. the patient""s abdomen had to be opened in order to reach the intestine. The basis for this expensive surgical technique, which is extremely demanding on the patient, is among other things that the intestine must be steadied for a precise operation, i.e. the intestine is removed from the respective area of the abdomen and is clamped or steadied by suitable means only then is the surgeon able to remove the tumor by means of precise steps and then close the intestine with sutures.
It is obvious that this intervention not only represents an expensive operation which is very demanding on the patient and could possible entail a great risk, particularly for elderly patients, but that it also incurs great costs which on the one hand are caused by the extensive surgical effort, and on the other by the patient""s mandatory long recovery period in the hospital.
Until now it was only possible to remove carcinomas from a maximum depth of about 20 cm from the anus into the intestine without the above mentioned procedure. This takes place by means of a so-called rectoscope. A rectoscope is a rigid cone-shaped tube part which is inserted into the anus and expands the latter by several centimeters. In that way the surgeon has enough space to reach the diseased area of the intestine with special tools and perform the operation.
One disadvantage of this surgical technique however is that the rectoscopy is only suitable for surgical interventions in an area of the colon within the first 20 cm from the anus, and only a few specialized surgeons are able to perform this operation. Starting with this problem it is the task of the invention to create a totally new type of device enabling both diagnoses as well as surgical interventions in the colon area through the end of the intestine.
This task is accomplished by a device with the features of claim 1. Further advantageous configurations of the invention are the subject of the remaining subclaims.
The invention begins with the following consideration: Through endoscopy it is already possible to examine the entire intestine of a patient through the anus by means of so-called coloscopes. These coloscopes are essentially used to visually examine the intestine through the anus. To that effect the distal end of the coloscope is equipped with a lighting device and optics, preferably a camera chip which is connected by lines inside an endoscope or coloscope shaft to a camera control at the end of the shaft. The camera control in turn is connected by a video processor to an external monitor on which the treating physician can see the areas to be examined. The distal end of the shaft being introduced into the cavity is designed to bend in all directions and can be manually curved like a finger by means of a handle, preferably via two steering wheels with a brake in the coloscope""s end-section. As a rule at least two channels pass through the coloscope shaft and open at the frontmost point of the distal end. When required, cleaning fluid can be directed through these channels to clean an area to be examined, or CO2 (air) to expand the cavity, or various working tools for example forceps or scissors for removing tissue samples, biopsy needles, heatable cutting wires, coagulation electrodes etc. can be inserted, and can also be manually actuated at the rear end of the coloscope shaft by means of operating wires or Bowden cables inside the internal channel. After the distal end has reached the respective area, a miniature forceps can for example be inserted into the channel from the rear section of the coloscope shaft and be pushed toward the distal end to remove a tissue sample. After the sample has been obtained, the forceps are withdrawn and removed from the channel so that further examination can proceed.
The coloscope generally has a lengthwise extended tubular form with a diameter of about 9 to 15 mm, and consists of a flexible material so that it can follow bends in the cavity to be examined, for example intestinal convolutions.
An endoscope of this type is known from the state of the art, for example according to U.S. Pat. No. 5,259,364, issued Nov. 9, 1993; and U.S. Pat. No. 5,568,968, issued Dec. 24, 1996. This endoscope essentially consists of an endoscope head or distal end to which an endoscope shaft made of a flexible tube body is connected, and an operating device at the rear end of the endoscope shaft. The operating device has a number of actuating wheels which are able to rotate in the endoscope shaft and are actively connected to the distal end by operating wires or Bowden cables located inside the endoscope shaft. A rear end-section of the endoscope furthermore contains a first driving or advancing device which exerts a driving force on the endoscope shaft through driving wheels.
At least the front section of the endoscope shaft has an invertible hose which is driven by a second driving or advancing device. Here the invertible hose consists of an inner hose section which can slide along the endoscope""s jacket surface and is inverted to form the front of an outer hose section in the endoscope""s distal end area. The front of the outer hose section is furthermore routed back to the second driving device and is attached to its housing. In the endoscope""s rear area the inner hose section is inverted to form an external rear hose section, which is also routed to the second driving device and is attached to the axial end of its housing opposite the front of the outer hose section.
Here the second driving device acts on the inner invertible hose section to move it in the axial direction of the endoscope. To that end the second driving device has a kind of sleeve or collar, which contracts in the radial direction and exerts frictional pressure against the inner hose section; it can also move like a piston in the endoscope""s axial direction. The radial pressure force of the sleeve is large enough so that at least a portion of the applied pressure force is transmitted through material deformation to the jacket surface of the endoscope shaft, thereby driving the endoscope shaft together with the inner invertible hose.
Since with this only type of driving by the second driving device the advancing speed (and path) of the invertible hose is only half as large in its inverted front area as that of the endoscope shaft, i.e. the shaft would exit from the invertible hose like a telescope with increasing penetration depth, the first driving device mentioned earlier exerts a braking force on the shaft which opposes the advancing force of the second driving device.
In that case the second driving device is synchronized with the first driving device so that, when both devices act together, the axial moving speed of the inner hose section is twice the speed of the endoscope shaft, where the latter slides in relation to the internal shaft (i.e. the distal end of the endoscope shaft moves at the same speed as the turned-up area of the invertible hose).
To facilitate the relative sliding motion between the endoscope shaft and the invertible hose, the state of the art according to further provides a lubricating device, whereby lubricating or sliding means can be forced between the inner hose section and the endoscope shaft as well as between the internal and the outer hose section. To that end the lubricating device has a cone-shaped bushing which slips over the endoscope shaft and acts as a seal with the rear turned-up area of the invertible hose which extends over the cone-shaped bushing. The lubricant, which is forced into the gap between the cone-shaped bushing and the endoscope shaft by a pump, spreads along the entire length between the inner hose section and the endoscope shaft, and excess lubricant flows into the cavity to be examined in the turned-up front area of the invertible hose.
From the in-house state of the art the inventor furthermore knows of an endoscope of this kind which uses a type of double invertible hose system as briefly described in the following:
This invertible hose system has an endoscope shaft that slides in a hose turned up on both sides, which can also be moved by a driving device acting on the inner hose section of the invertible hose. The driving device has at least one continuous advancing means which can be radially pressed onto the inner hose section in order to essentially move the latter continuously in the axial direction of the shaft. This has the great advantage that the continuous advance of the invertible hose system is accurately controllable, for example to precisely locate the distal end of an endoscope.
It is provided in this case that the pressure force exerted by the advancing means on the inner hose section must be such that the shaft makes direct friction contact with the inner hose section, at least in the area of the advancing means. The advancing means is provided by one or several friction wheels which can be preloaded with a predetermined or adjustable pressure force against the inner hose section, so that on the one hand a continuous, and on the other a slip-free advance of the endoscope shaft into a patient""s cavity can be assured.
The driving device furthermore has a fixture to synchronize the shaft movement with the invertible hose movement. This can be a rear or front-end fitting or a clamp that is axially affixed to the shaft against which, depending on the advancing direction, the rear or the front turned-up area of the invertible hose abuts and slides, so that the invertible hose can exert a braking force through the rear or the front-end fitting against the force that presently advances the shaft. As an alternative, the synchronization fixture can be a roller or spindle drive acting on the rear end-section of the shaft, which is synchronized with the invertible hose drive so that the advancing speed of the shaft is half the advancing speed of the inner hose section.
The invertible hose can have a guide part or a bushing made of a stiff material which is pulled over the inner hose section and forms an annular gap, where the free ends of outer hose sections are affixed to two axial end-sections of the gap and form two axially separated inverted areas when the inner hose section is turned up and routed back. This bushing now offers the possibility of receiving or attaching a driving device directly to the inner hose section, so that the external size of the entire invertible hose system remains compact and thus improves its maneuverability.
The bushing may further be provided with a number of openings or lengthwise slits in its central section, preferably at the same angular separation from each other. The invertible hose then forms an environmentally sealed empty space over the inner hose section, the outer hose sections as well as the bushing, which only can be accessed through the openings in the bushing. In this way the bushing is constructively prepared to receive a driving device, whose propelling means can contact the inner hose section through the lengthwise slits. Furthermore the bushing is advantageously provided with grooves extending in the axial direction, which open at the front face of the bushing. During operation of the system, these grooves facilitate the forced shifting of the lubricant in the cited cavity through the bushing.
The driving device of the invertible hose system can have a two-part collapsible housing which can be placed around the bushing of the invertible hose in the manner of a sleeve, and in the collapsed state forms an externally sealed empty space with the bushing in which friction wheels are located, which can be pressed against the inner hose section through the openings of the bushing when the housing is collapsed. This achieves a compact, self-enclosed (integrated and not additive) construction of the system increasing the maneuverability and functionality of the interacting parts.
The friction wheels of the internally known endoscope are furthermore placed in springy fashion against the housing, in order to exert a predetermined pressure force that corresponds to the spring force, or which is also adjustable against the inner hose section, and also to allow the use of slightly variable diameters of the shaft. In addition, the running surfaces of the friction wheels can be provided or designed with an anti-slip coating.
The endoscope also has the special technical feature where a connector is installed on the driving device housing for supplying a lubricant which can be pressed into the empty space of the invertible hose through the openings in the bushing. On the one hand this allows to lubricate the drive mechanism itself, and on the other the relative sliding motion of the internal and outer hose sections, thereby reducing the friction.
As a further aspect of the internally known endoscope, the invertible hose system is designed with a lubricating device for pressing lubricant into an annular gap between the shaft and the inner hose section, where at least one radially running hole or perforation is placed in the shaft wall, which opens into the annular gap and is connected to a lubricating device. In this way lubricant can be supplied directly into the annular gap at a low cost.
As an alternative, the lubricating device comprises a rear clamping part, which is affixed to the shaft and has at least one lubricant injection spout. This spout protrudes into the annular gap and enables pressing lubricant through a hollow needle formed inside the spout.
Among other things the lubrication system for supplying lubricant to the invertible hose system has one or two pressure vessels, each able to hold a lubricant bag or bellows designed as a one-way article, which can be fluidly connected by a coupling to supply lines of the shaft and the driving device.
The basic idea of the invention consists in reworking a known endoscope, preferably the one known internally, into an auxiliary surgical means for performing diagnoses and operations in the colon by means of microsurgical techniques, where the endoscope shaft which was described earlier by means of the internal state of the art, is replaced by a flexible access tube produced in accordance with the invention, which in the manner of a trocar makes it possible for surgical tools and diagnostic instruments to access the area to be operated. Experiments have shown that the colon has an elasticity which allows its internal diameter to expand to over 25 mm. Based on these results it is possible to develop a flexible access tube in conjunction with an invertible hose transport system, whose internal diameter allows the insertion of surgical tools and other instruments, such as for example optics or a coloscope shaft into body cavities like the colon e.g.
According to patent claim 1, the access tube of the invention therefore has a flexible outer jacket and a radially separated flexible internal jacket which form a hollow space for supply and function channels between them.
The supply channels are preferably designed as air or CO2 lines and/or as flushing channels, while the function channels contain Bowden cables or hydraulic fluid to actuate the access tube, and camera connection lines for video chips and optical fibers, preferably glass fibers, located at the distal end of the access tube which enable illuminating the cavity to be examined.
The correspondingly large inside diameter of the internal jacket, and the location of the supply and function channels in the space between the external and the internal jackets form a sufficiently large access channel that extends from the anus to any place in the colon at least below the second sigma loop and possibly beyond, but can also be inserted into other body cavities.
With the help of the flexible access tube of the invention it is therefore possible to accurately advance from the anus to the desired area in the colon or beyond it, regardless of the distance from the anus. This creates a quasi surgical channel comparable to a trocar, through which the desired probes and medical tools can be inserted either simultaneously or successively in a simple manner. The risk of injuring the intestinal wall while the surgical tools or examination probes are inserted is thereby eliminated. The operation can proceed faster since no risk of an intestinal wall injury needs to be feared, for example when changing one tool for another, since these procedures only occur inside the trocar, i.e. the instruments are only able to contact the inner wall of the trocar but not the intestinal wall itself.
As mentioned earlier, the trocar interspace, i.e. the space between the internal and external jackets can be used in the most diverse ways. For example two or more air or CO2 channels can be located therein. This allows the intestine to be inflated and thus more uniformly unfolded. In addition two or more suction and/or flushing channels can be provided. This allows the operating field and the integrated optics of the trocar to be flushed, or flushing can take place in predetermined directions. Beyond that several illumination channels can also be formed in order to improve the view and enable to illuminate in predetermined directions.
At its rearmost end-section the trocar of the invention is additionally equipped with a trocar valve and/or a seal. As previously explained, the supply channels are designed to provide CO2 or air, but also flushing liquid. As long as no surgical instrument is inserted into the trocar, the CO2 and/or the flushing liquid escape uncontrolled through the inner trocar space. The trocar valve, preferably in the form of an electromagnetic flap valve, is provided to prevent this by closing the inner trocar space against the outside. This valve opens as soon as a surgical instrument is introduced into the trocar, which causes only minor leaks. These can be additionally minimized with a seal between the trocar and the surgical instrument.
The cited flap valve proved to be particularly suitable with a one-piece or also a two-piece flap with or without a hinge. But inflatable annular packing or hoses around the trocar""s internal circumference can be envisioned as valves and simultaneously as seals.
Finally, special function channels can be provided between the external and internal trocar jackets, which are closed at the trocar""s distal end and at the rear end are preferably connected to a vacuuming or a pressurizing device. Vacuuming in particular causes the external and internal trocar jackets to press against each other, at least in the area of these function channels, thereby achieving a stiffening or freezing of the flexible trocar""s attitude. This is particularly important during the operating phase when the trocar must be kept as rigid and the intestine as unyielding as possible.
Alternatively to the vacuuming process, the special function channels can also be pressurized to achieve a certain temporary rigidity of the trocar. It can also be envisioned to spray a fluid or a gel into the function channels, which hardens and then liquefies under predetermined conditions, e.g. in a temperature-dependent manner.